A woman in her 20s presented with haematemesis, post-prandial abdominal pain, weight loss and anaemia. Imaging revealed a non-enhancing mass in the retroperitoneal space along the mesenteric plane, encasing the porto-mesenteric vasculature. Endoscopy showed oesophageal varices. She was diagnosed with sclerosing mesenteritis, causing extrinsic compression of the portal vein and superior mesenteric artery. She underwent endoscopic variceal ligation and received prednisolone and tamoxifen. After 3 months, her post-prandial pain improved, and she did not have further bleeding episodes.